The present invention relates to managing surface water generally and to pollution control and recycling more specifically.
Sometimes when it rains, it pours. When it pours, leaves, dirt, debris, oils and solvents on the surfaces of roads and streets are swept by surface water runoff toward municipal sewer systems where this material may be collected and processed. Unfortunately, this material often flows directly into lakes or rivers. The surface water may enter the sewer system at inlets along a street curb or catch basin and exit the sewer system through large pipes. Oils and chemicals in the run off will contaminate the bodies of water into which they are dumped. This is referred to as xe2x80x9cnonpoint source pollutionxe2x80x9d by some regulating authorities. A nonpoint source of pollution is basically pollution without a single point of origin, or pollution that is not introduced into a receiving body of water from a specific outlet. Some other examples of nonpoint sources may include agriculture, forestry, mining, construction, and land disposal. Because this type of pollution has no particular point of origin, it is not only difficult to collect this pollution, but is also difficult to monitor and prevent the pollution.
Thus, there remains a need for a better way to manage the collection of the materials swept into the sewer system.
According to its major aspects and briefly recited, the present invention is an insert to be placed into an inlet or outlet of a municipal sewer system. The insert comprises a holder such as a mesh bag or pillow and a water permeable, hydrophobic oil and solvent absorber carried by the holder. The holder will both hold a sufficient quantity of the absorber to be effective in absorbing oils and solvents for a suitable period of time but also to hold it in such a way as to expose it to the in-rushing or out-rushing surface water so that the absorber is exposed to the oil- and solvent-bearing surface water in order to extract at least a portion of the solvents and oils. In addition, the device may also include a trap for large particulate such as leaves and twigs.
An important feature of the present invention is the use of a hydrophobic, water-permeable absorber. The absorber absorbs oils and solvents but not water, and it allows water to pass through readily. The absorber, moreover, can be cleaned and reused, and the solvent and oil recovered. Furthermore, the absorber can be tested for the presence of various chemicals that are absorbed as the water passes through it. This testing capability provides a convenient way to identify the chemical concentrations and flow rates for in-rushing and out-rushing surface water.
Another important feature of the present invention is the holder. The holder, as noted above, serves two functions: it not only holds an effective quantity of the absorber, but it holds the absorber so that it is exposed to the in-rushing or out-rushing surface water so that the oils and solvents in the water can be absorbed. With the absorber in the holder, the insert becomes a convenient, replaceable, and recyclable cartridge for insertion into the inlet or outlet of the sewer system to absorb oils and solvents but readily pass the surface water.
Still another feature of the invention is its placement. By being placed at the inlet or outlet of the sewer system, it is easily installed and removed, readily checked, and more accessible for servicing and maintenance than if placed further into the interior to the sewer system.
These and other features and their advantages will be clear to those skilled in the art of surface water management from a careful reading of the Detailed Description of Preferred Embodiments, accompanied by the following drawings.